Windowing expression may loose its input in some cases

drop table if exists sss;
 CREATE TABLE `sss`(
   `user_id` bigint,
   `user_mid` string
 )
 PARTITIONED BY (
   `dt` string)
STORED AS ORC
   ;

insert into sss partition(dt='part1') VALUES (12345,'user_mid v1'),(12345,'user_mid v1'),(12345,'user_mid v1'),(12345,'user_mid v1'),(12345,'user_mid v1');


set hive.auto.convert.join.noconditionaltask.size=1;
WITH
     unioned_user AS (
         SELECT
             *,
             row_number() OVER (PARTITION BY user_mid ORDER BY dt ASC) AS r_asc,
             row_number() OVER (PARTITION BY user_mid ORDER BY dt DESC) AS r_desc
         FROM (
             SELECT DISTINCT
                 dt,
                 user_mid
             FROM sss
             WHERE dt = '20210228'
             UNION ALL
             SELECT DISTINCT
                dt,
                 user_mid
             FROM sss
         ) AS uni
     ),
     merged_user AS (
         SELECT
             a.user_mid
         FROM (SELECT * FROM unioned_user WHERE r_asc = 1) AS a
         INNER JOIN (SELECT * FROM unioned_user WHERE r_desc = 1) AS d
         ON a.user_mid = d.user_mid
     )
 Select count(*) from merged_user;